Reducing aluminosilicate scale in the bayer process

ABSTRACT

The invention provides methods and compositions for inhibiting the accumulation of DSP scale in the liquor circuit of Bayer process equipment. The method includes adding one or more particular silane based small molecules to the liquor fluid circuit. These scale inhibitors reduce DSP scale formation and thereby increase fluid throughput, increase the amount of time Bayer process equipment can be operational and reduce the need for expensive and dangerous acid washes of Bayer process equipment. As a result, the invention provides a significant reduction in the total cost of operating a Bayer process.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 12/567,116 filed on Sep. 25, 2009.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

BACKGROUND OF THE INVENTION

The invention relates to compositions, methods, and apparatuses forimproving treating scale in various industrial process streams, inparticular certain silane based small molecules that have been found tobe particularly effective in treating aluminosilicate scale in a Bayerprocess stream.

As described among other places in U.S. Pat. No. 6,814,873 the contentsof which are incorporated by reference in their entirety, the Bayerprocess is used to manufacture alumina from Bauxite ore. The processuses caustic solution to extract soluble alumina values from thebauxite. After dissolution of the alumina values from the bauxite andremoval of insoluble waste material from the process stream the solublealumina is precipitated as solid alumina trihydrate. The remainingcaustic solution known as “liquor” and/or “spent liquor” is thenrecycled back to earlier stages in the process and is used to treatfresh bauxite. It thus forms a fluid circuit. For the purposes of thisapplication, this description defines the term “liquor”. The recyclingof liquor within the fluid circuit however has its own complexities.

Bauxite often contains silica in various forms and amounts. Some of thesilica is unreactive so it does not dissolve and remains as solidmaterial within the Bayer circuit. Other forms of silica (for exampleclays) are reactive and dissolve in caustic when added into Bayerprocess liquors, thus increasing the silica concentration in the liquor.As liquor flows repeatedly through the circuit of the Bayer process, theconcentration of silica in the liquor further increases, eventually to apoint where it reacts with aluminum and soda to form insolublealuminosilicate particles. Aluminosilicate solid is observed in at leasttwo forms, sodalite and cancrinite. These and other forms ofaluminosilicate are commonly referred to, and for the purposes of thisapplication define, the terms “desilication product” or “DSP”.

DSP can have a formula of 3(Na₂O.Al₂O₃.2SiO₂.0-2H₂O)*2NaX where Xrepresents OH⁻, Cl⁻, CO₃ ²⁻, SO₄ ²⁻. Because DSP has an inversesolubility (precipitation increases at higher temperatures) and it canprecipitate as fine scales of hard insoluble crystalline solids, itsaccumulation in Bayer process equipment is problematic. As DSPaccumulates in Bayer process pipes, vessels, heat transfer equipment,and other process equipment, it forms flow bottlenecks and obstructionsand can adversely affect liquor throughput. In addition because of itsthermal conductivity properties, DSP scales on heat exchanger surfacesreduce the efficiency of heat exchangers.

These adverse effects are typically managed through a descaling regime,which involves process equipment being taken off line and the scalebeing physically or chemically treated and removed. A consequence ofthis type of regime is significant and regular periods of down-time forcritical equipment. Additionally as part of the descaling process theuse of hazardous concentrated acids such as sulfuric acid are oftenemployed and this constitutes an undesirable safety hazard.

Another way Bayer process operators manage the buildup of silicaconcentration in the liquor is to deliberately precipitate DSP as freecrystals rather than as scale. Typically a “desilication” step in theBayer process is used to reduce the concentration of silica in solutionby precipitation of silica as DSP, as a free precipitate. While suchdesilication reduces the overall silica concentration within the liquor,total elimination of all silica from solution is impractical andchanging process conditions within various parts of the circuit (forexample within heat exchangers) can lead to changes in the solubility ofDSP, resulting in consequent precipitation as scale.

Previous attempts at controlling and/or reducing DSP scale in the Bayerprocess have included adding polymer materials containing three alkyloxygroups bonded to one silicon atom as described in U.S. Pat. No.6,814,873 B2, US published applications 2004/0162406 A1, 2004/0011744A1, 2005/0010008 A2, international published application WO 2008/045677A1, and published article Max HTTM Sodalite Scale Inhibitor: PlantExperience and Impact on the Process, by Donald Spitzer et. al., Pages57-62, Light Metals 2008, (2008) all of whose contents are incorporatedby reference in their entirety.

Manufacturing and use of these trialkoxysilane-grafted polymers howevercan involve unwanted degrees of viscosity, making handling anddispersion of the polymer through the Bayer process liquor problematic.Other previous attempts to address foulant buildup are described in U.S.Pat. Nos. 5,650,072 and 5,314,626 both of which are incorporated byreference in their entirety.

Thus while a range of methods are available to Bayer process operatorsto manage and control DSP scale formation, there is a clear need for,and utility in, an improved method of preventing or reducing DSP scaleformation on Bayer process equipment. The art described in this sectionis not intended to constitute an admission that any patent, publicationor other information referred to herein is “prior art” with respect tothis invention, unless specifically designated as such. In addition,this section should not be construed to mean that a search has been madeor that no other pertinent information as defined in 37 C.F.R. §1.56(a)exists.

BRIEF SUMMARY OF THE INVENTION

To satisfy the long-felt but unsolved needs identified above, at leastone embodiment of the invention is directed towards a method forreducing siliceous scale in a Bayer process comprising the step ofadding to a Bayer liquor an aluminosilicate scale inhibiting amount ofreaction product between an amine-containing molecule and anamine-reactive molecule containing at least one amine-reactive group permolecule and at least one —Si(OR)n group per molecule, where n=1, 2, or3, and R=H, C1-C12 Alkyl, Aryl, Na, K, Li, or NH4, or a mixture of suchreaction products.

Another embodiment is directed towards a method for reducing siliceousscale in a Bayer process comprising the step of adding to a Bayer liquoran efficacious amount of reaction product between: 1) anamine-containing small molecule, and 2) an amine-reactive small moleculecontaining at least one amine-reactive group per molecule and at leastone —Si(OR)n group per molecule, where n=1, 2, or 3, and R=H, C1-C12Alkyl, Aryl, Na, K, Li, or NH4, or a mixture of such reaction products,and 3) a non-polymeric amine reactive hydrophobic hydrocarbon.

At least one embodiment is directed towards a method of reducing DSP ina Bayer process comprising the step of adding to the Bayer processstream an aluminosilicate scale inhibiting amount of a mixture ofproducts as defined above.

Additional features and advantages are described herein, and will beapparent from, the following Detailed Description.

DETAILED DESCRIPTION OF THE INVENTION

The following definitions are provided to determine how terms used inthis application, and in particular how the claims, are to be construed.The organization of the definitions is for convenience only and is notintended to limit any of the definitions to any particular category.

“Polymer” means a chemical compound comprising essentially repeatingstructural units each containing two or more atoms. While many polymershave large molecular weights of greater than 500, some polymers such aspolyethylene can have molecular weights of less than 500. Polymerincludes copolymers and homo polymers.

“Small molecule” means a chemical compound comprising essentiallynon-repeating structural units. Because an oligomer (with more than 10repeating units) and a polymer are essentially comprised of repeatingstructural units, they are not small molecules. Small molecules can havemolecular weights above and below 500. The terms “small molecule” and“polymer” are mutually exclusive.

“Foulant” means a material deposit that accumulates on equipment duringthe operation of a manufacturing and/or chemical process which may beunwanted and which may impair the cost and/or efficiency of the process.DSP is a type of foulant.

“Amine” means a molecule containing one or more nitrogen atoms andhaving at least one secondary amine or primary amine group. By thisdefinition, monoamines such as dodecylamine, diamines such ashexanediamine, and triamines such as diethylenetriamine, are all amines.

“GPS” is 3-glycidoxypropyltrimethoxysilane.

“Alkyloxy” means having the structure of OX where X is a hydrocarbon andO is oxygen. It can also be used interchangeably with the term “alkoxy”.Typically in this application, the oxygen is bonded both to the X groupas well as to a silicon atom of the small molecule. When X is C₁ thealkyloxy group consists of a methyl group bonded to the oxygen atom.When X is C₂ the alkyloxy group consists of an ethyl group bonded to theoxygen atom. When X is C₃ the alkyloxy group consists of a propyl groupbonded to the oxygen atom. When X is C₄ the alkyloxy group consists of abutyl group bonded to the oxygen atom. When X is C₅ the alkyloxy groupconsists of a pentyl group bonded to the oxygen atom. When X is C₆ thealkyloxy group consists of a hexyl group bonded to the oxygen atom.

“Monoalkyloxy” means that attached to a silicon atom is one alkyloxygroup.

“Dialkyloxy” means that attached to a silicon atom are two alkyloxygroups.

“Trialkyloxy” means that attached to a silicon atom are three alkyloxygroups.

“Synthetic Liquor” or “Synthetic Spent Liquor” is a laboratory createdliquid used for experimentation whose composition in respect to alumina,soda, and caustic corresponds with the liquor produced by recyclingthrough the Bayer process.

“Bayer Liquor” is actual liquor that has run through a Bayer process inan industrial facility.

In the event that the above definitions or a definition stated elsewherein this application is inconsistent with a meaning (explicit orimplicit) which is commonly used, in a dictionary, or stated in a sourceincorporated by reference into this application, the application and theclaim terms in particular are understood to be construed according tothe definition in this application, and not according to the commondefinition, dictionary definition, or the definition that wasincorporated by reference.

In the Bayer process for manufacturing alumina, bauxite ore passesthrough a grinding stage and alumina, together with some impuritiesincluding silica, are dissolved in added liquor. The mixture thentypically passes through a desilication stage where silica isdeliberately precipitated as DSP to reduce the amount of silica insolution. The slurry is passed on to a digestion stage where anyremaining reactive silica dissolves, thus again increasing theconcentration of silica in solution which may subsequently form more DSPas the process temperature increases. The liquor is later separated fromundissolved solids, and alumina is recovered by precipitation asgibbsite. The spent liquor completes its circuit as it passes through aheat exchanger and back into the grinding stage. DSP scale accumulatesthroughout the Bayer process but particularly at the digestion stage andmost particularly at or near the heat exchanger, where the recycledliquor passes through.

In this invention, it was discovered that dosing of various types ofsilane-based products can reduce the amount of DSP scale formed.

In at least one embodiment of the invention, an effective concentrationof a silane-based small molecule product is added to some point or stagein the liquor circuit of the Bayer process, which minimizes or preventsthe accumulation of DSP on vessels or equipment along the liquorcircuit.

In at least one embodiment, the small molecule comprises the reactionproduct between an amine and at least one amine-reactive silane, thesilicon of the silane can be monoalkyloxy, dialkyloxy, trialkyloxy ortrihydroxy.

In at least one embodiment the small molecule is a reaction productbetween an amine-containing small molecule and an amine-reactivemolecule containing at least one amine-reactive group per molecule andat least one —Si(OR)_(n) group per molecule, where n=1, 2, or 3, andR=H, C1-C12 Alkyl, Aryl, Na, K, Li, or NH₄, or a mixture of suchreaction products.

In at least one embodiment, the amine molecule is selected from a linearor branched, aliphatic or cycloaliphatic monoamines or diamines. Thetotal number of carbon atoms in the amine is preferred to be less than30 and more preferred to be less than 20. In at least one embodiment theamine is selected from a list consisting of: isophoronediamine,xylenediamine, bis(aminomethyl)cyclohexane, hexanediamine,C,C,C-trimethylhexanediamine, methylene bis(aminocyclohexane), saturatedfatty amines, unsaturated fatty amines such as oleylamine and soyamine,N-fatty-1,3-propanediamine such as cocoalkylpropanediamine,oleylpropanediamine, dodecylpropanediamine, hydrogenizedtallowalkylpropanediamine, and tallowalkylpropanediamine and anycombination thereof.

In at least one embodiment, a particularly effective small moleculecomprises the reaction product of an amine small molecule together with3-glycidoxypropyltrialkoxysilane (GPS).

In at least one embodiment the added small molecule is TG14. For thepurposes of this application, the definition of TG14 is a small moleculehaving the structure of:

where the M, J, and R groups are each one selected from the listconsisting of C₁-C₆ alkyloxy, hydrogen, hydroxide, or C₁-C₆ alkylgroups. M, J, and R can each be different or can be the same as some orall of the other groups. One form of TG14 is TG14-R, which is describedin U.S. Pat. No. 6,867,318. In TG14-R the M, J, and R groups are all thesame C₁-C₆ alkyloxy group.

In at least one embodiment the small molecule is a monoalkyloxy TG14. Inat least one embodiment the small molecule is a dialkyloxy TG14. In atleast one embodiment the small molecule is a trialkyloxy TG14. In atleast one embodiment the small molecule is a trihydroxy TG14.

In at least one embodiment the added small molecule is DG12. DG12 is adodecylamine with one or more silane groups having one, two, or threealkyloxy groups on each silane group. For purposes of this application,the definition of DG12 is a small molecule having the structure of:

where the M, J, and R groups are each one selected from the listconsisting of C₁-C₆ alkyloxy, hydrogen, hydroxide, or C₁-C₆ alkylgroups. M, J, and R can each be different or can be the same as some orall of the other groups. One form of DG12 is DG12-R, which is atrialkyloxy small molecule.

In at least one embodiment the small molecule is a monoalkyloxy DG12. Inat least one embodiment the small molecule is a dialkyloxy DG12. In atleast one embodiment the small molecule is a trialkyloxy DG12. In atleast one embodiment the small molecule is a trihydroxy DG12.

The small molecule can also be selected from the list consisting ofmono, di, tri or tetramine-epoxy functional silane adduct, mono, di, trior tetramine-isocyanato functional silane adduct, TG14, DG12, anyreaction product between a small molecule amine and an amine-reactivefunctional silane, and any combination thereof.

In at least one embodiment the small molecule is a reaction productbetween 1) an amine-containing small molecule, 2) an amine-reactivemolecule containing one amine-reactive group per molecule and at leastone —Si(OR)_(n) group per molecule, where n=1, 2, or 3, and R=H, C1-C12Alkyl, Aryl, Na, K, Li, or NH₄, or a mixture of such reaction products,together with 3) an amine reactive hydrophobic molecule.

In at least one embodiment, an amine small molecule is reacted with both3-glycidoxypropyltrialkoxysilane (GPS) and a hydrophobic molecule toform a DSP inhibition composition. The hydrophobic molecule is anamine-reactive compound having an amine-reactive functional group suchas glycidyl, chloro, bromo, or isocyanato groups. Besides theamine-reactive group, the hydrophobic molecule has at least one C₃-C₂₂hydrophobic carbon chain, aromatic or aliphatic, linear or branched. Aparticularly effective hydrophobic molecule is 2-ethylhexyl glycidylether (E) the structure of which is shown below:

Other representative hydrophobic molecules are nonylphenolglycidylethers, which are described in International Patent ApplicationWO 08045677A1.

In at least one embodiment, the amine molecule is selected from linearor branched, aliphatic or cycloaliphatic monoamines or diamines. Thetotal number of carbon atoms in the amine is preferred to be less than30 and more preferred to be less than 20.

In at least one embodiment the amine is selected from a list consistingof: isophoronediamine, xylenediamine, bis(aminomethyl)cyclohexane,hexanediamine, C,C,C-trimethylhexanediamine, methylenebis(aminocyclohexane), saturated fatty amines, unsaturated fatty aminessuch as oleylamine and soyamine, N-fatty-1,3-propanediamine such ascocoalkylpropanediamine, oleylpropanediamine, dodecylpropanediamine,hydrogenized tallowalkylpropanediamine, and tallowalkylpropanediamineand any combination thereof.

In at least one embodiment the amine is isophoronediamine (A) whosestructure is:

When isophoronediamine is reacted with 3-glycidoxypropyltrialkoxysilaneand 2-ethylhexylglycidyl ether at 1:1:1 molar ratio, the resultinginhibition composition is primarily made of a molecule that has anisophoronediamine backbone with a single silane unit and a singlehydrophobic unit.

Two representative structures of such amine-silane-hydrophobe adductsare shown below where the amine containing molecules are hexanediamineand isophoronediamine respectively, and wherein M, J, and R groups areeach one independently selected from the list consisting of C₁-C₆alkyloxy, hydrogen, hydroxide, or C₁-C₆ alkyl groups.

In at least one embodiment, a method for reducing siliceous scale in aBayer process comprises the step of adding to a Bayer liquor a scaleinhibiting amount of a composition of matter, the composition comprisinga reaction product made from reacting:

-   -   an amine-containing small molecule having at least one        —Si(OR)_(n) per molecule, where n=1, 2, or 3, and R=H, C1-C12        Alkyl, Aryl, Na, K, Li, or NH₄, and        -   an amine-reactive hydrophobic molecule with a molecular            weight of less than 500 daltons. The amine-containing small            molecule can be any one or a combination of the following            molecules: aminoethylaminopropyltrialkoxysilane,            aminoethylaminopropyldialkoxysilane, and            aminoethylaminopropylmonoalkoxysilane. The amine-reactive            hydrophobic small molecule can be selected from a group            consisting of C₃-C₂₂ glycidyl ether, C₃-C₂₂ isocyanate,            C₃-C₂₂ chloride, C₃-C₂₂ bromide, C₃-C₂₂ iodide, C₃-C₂₂            sulfate ester, C₃-C₂₂ phenolglycidyl ether, and any            combination thereof.

These silane-based small molecules reduce the amount of DSP scale formedand thereby prevents its accumulation on Bayer process equipment.

The effectiveness of these small molecules was unexpected as the priorart teaches that only high molecular weight polymers are effective.Polymer effectiveness was presumed to depend on their hydrophobic natureand their size. This was confirmed by the fact that cross-linkedpolymers are even more effective than single chain polymers. As a resultit was assumed that small molecules only serve as building blocks forthese polymers and are not effective in their own right. (WO 2008/045677[0030]). Furthermore, the scientific literature states “small moleculescontaining” . . . “[an] Si—O₃ grouping are not effective in preventingsodalite scaling” . . . because . . . “[t]he bulky group” . . . “isessential [in] keeping the molecule from being incorporated into thegrowing sodalite.” Page 57¶9 Light Metals 2008, (2008). However it hasrecently been discovered that in fact, as further explained in theprovided examples, small molecules such as those described herein areactually effective at reducing DSP scale.

It is believed that there are at least three advantages to using a smallmolecule-based inhibitor as opposed to a polymeric inhibitor withmultiple repeating units of silane and hydrophobes. A first advantage isthat the smaller molecular weight of the product means that there are alarger number of active, inhibiting moieties available around the DSPseed crystal sites at the DSP formation stage. A second advantage isthat the lower molecular weight allows for an increased rate ofdiffusion of the inhibitor, which in turn favors fast attachment of theinhibitor molecules onto DSP seed crystals. A third advantage is thatthe lower molecular weight avoids high product viscosity and so makeshandling and injection into the Bayer process stream more convenient andeffective.

EXAMPLES

The foregoing may be better understood by reference to the followingexamples, which are presented for purposes of illustration and are notintended to limit the scope of the invention. In particular the examplesdemonstrate representative examples of principles innate to theinvention and these principles are not strictly limited to the specificcondition recited in these examples. As a result it should be understoodthat the invention encompasses various changes and modifications to theexamples described herein and such changes and modifications can be madewithout departing from the spirit and scope of the invention and withoutdiminishing its intended advantages. It is therefore intended that suchchanges and modifications be covered by the appended claims.

Example 1

Polypropylene bottles and a temperature controlled rotary water bathwere used under isothermal conditions for batch desilicationexperiments. Synthetic spent Bayer liquor was prepared on the same dayor one day prior to the experiment. Typical analysis for the syntheticliquor used was:

Alumina (A): 84.62 g/L as Al₂O₃; Caustic (C): 238.42 g/L as Na₂CO₃;Ratio of A to C: 0.355.

A series of tests were conducted by adding the specified dose of TG14and DG12 to the bottles containing synthetic spent Bayer liquor (150-200mL). The synthetic liquor was heated in the water bath and as thedesired temperature (95° C.) was reached, sodium metasilicate solutionwas added. (A calculated amount to give the starting SiO₂ concentrationof 0.05M was added.) The resulting solutions were heated and held at 95°C. for the duration of the test (4 hours). Final solutions were filteredthrough a 0.45 μm membrane to collect solids, which were washed with hotde-ionized water and air-dried. Table 1 shows the percent of DSP massprecipitated relative to an undosed control test.

TABLE 1 Percent DSP Mass precipitated in tests versus undosed controlsample mass. % DSP Mass Dosage, Precipitated vs. Products ppm ControlControl 0 100 TG14 200 34 DG12 200 69

The results showed that TG14 and DG12 reduce the mass of the resultingprecipitate indicating inhibition of DSP formation.

Example 2

A series of further tests were conducted in a similar manner to thatdescribed in example 1 using Bayer process liquor from two operationalrefineries. In these and subsequent examples the following method wasemployed:

To a series of polypropylene bottles containing plant spent liquor (200mL each), a 20 mL sample of 117 g/L Na₂SiO₃.5H₂O solution was added (3.0g/L as SiO₂). To selected bottles, a specified dose of individualinhibitor product was also added. Duplicate bottles for each dose ofeach inhibitor were used, together with duplicate undosed controlsamples in each test. The resulting liquor mixtures were heated in arotating water bath with temperature held constantly at 95° C.throughout the duration of the test (4 hours) so as to induceprecipitation of DSP. After 4 hours, the contents of each bottle wereindividually filtered to collect the solids, which were washed with hotde-ionized water and dried at room temperature overnight. Theeffectiveness of the additives was determined by comparing the mass ofthe solid obtained from samples where an inhibitor was added, to that ofthe undosed control samples (without additives).

Tables 2 displays the results of individual tests using inhibitormolecules produced by the reaction of a small molecule amine with theamine-reactive silane, 3-glycidoxypropyltrialkoxysi lane (GPS).Inhibition results are displayed as the mass of DSP precipitated fromtreated samples as a percentage of the mass of DSP precipitated fromuntreated control samples. Average values of duplicate samples for alltreatments were used to calculate the percent precipitated.

The individual amines used to produce the various reagents and thenomenclature used to identify the amines is as follows:

A=Isophoronediamine T=C,C,C-trimethylhexanediamine S=SoyamineO=Oleylamine

The ratio denoted in table 2 indicates the molar ratio of amine to GPS(as amine:GPS) used in the reaction to produce the active small moleculeproducts. Variation of the molar ratio was observed to result inproducts displaying a variety of inhibitory properties.

TABLE 2 Inhibition of DSP by small molecule adducts of amine/silanereaction. % DSP Amine- Product Precipitated Active Dose vs Undosed AmineSilane Hydrophobe Ratio (ppm) control A GPS — 1:4 25 86 T GPS — 1:4 5095 S GPS — 1:2 40 72 O GPS — 1:2 40 73

In all cases the addition of the reaction product of the amine and GPSis shown to result in a lower mass of DSP precipitated than the mass ofuntreated samples. This indicates inhibition of the precipitation of DSPwhen such reagents are added to the Bayer liquor.

Example 3

Similar tests were conducted to assess the effect of reagents comprisingthe reaction products of 1) a small molecule amine, 2) an amine reactivesilane and 3) an amine reactive hydrophobe. The method used was the sameas that described in example 2 and reagents used to produce the activecomponents are listed in table 3 together with the activity as measuredby percent of DSP precipitated compared to an undosed control sample.

Again, in all cases the precipitation of DSP is reduced by addition ofthe reaction products as specified, indicating that inhibition of DSPprecipitation is achieved by application of the relevant small moleculesto the Bayer liquor.

Nomenclature used in Table 3 is the same as that used for Table 2 withthe addition of:

ED=N-[3-(Trimethoxysilyl)propyl]ethylenediamineP=4-nonylphenolglycidyl etherE=2-Ethylhexylglycidyl ether

H=1,6-Hexanediamine

TABLE 3 Inhibition of DSP by small molecule adducts ofamine/silane/hydrophobe reaction. % DSP Amine- Product PrecipitatedActive Dose vs Undosed Amine Silane Hydrophobe Ratio (ppm) control A GPSP 1:3:1 40 75 A GPS E 1:2:2 40 96 A GPS E 1:2:1 40 63 A GPS E 1:1:1 5018 A GPS E 1:1:1 20 67 ED — E 1:0:1 80 44 A GPS E 1:1:0.5 20 57 T GPS E1:1:1 6 2 H GPS E 1:1:0.3 9 7

While this invention may be embodied in many different forms, there aredescribed in detail herein specific preferred embodiments of theinvention. The present disclosure is an exemplification of theprinciples of the invention and is not intended to limit the inventionto the particular embodiments illustrated. All patents, patentapplications, scientific papers, and any other referenced materialsmentioned herein are incorporated by reference in their entirety.Furthermore, the invention encompasses any possible combination of someor all of the various embodiments mentioned herein, described hereinand/or incorporated herein. In addition the invention encompasses anypossible combination that also specifically excludes any one or some ofthe various embodiments mentioned herein, described herein and/orincorporated herein.

The above disclosure is intended to be illustrative and not exhaustive.This description will suggest many variations and alternatives to one ofordinary skill in this art. All these alternatives and variations areintended to be included within the scope of the claims where the term“comprising” means “including, but not limited to”. Those familiar withthe art may recognize other equivalents to the specific embodimentsdescribed herein which equivalents are also intended to be encompassedby the claims.

All ranges and parameters disclosed herein are understood to encompassany and all subranges subsumed therein, and every number between theendpoints. For example, a stated range of “1 to 10” should be consideredto include any and all subranges between (and inclusive of) the minimumvalue of 1 and the maximum value of 10; that is, all subranges beginningwith a minimum value of 1 or more, (e.g. 1 to 6.1), and ending with amaximum value of 10 or less, (e.g. 2.3 to 9.4, 3 to 8, 4 to 7), andfinally to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 containedwithin the range. All percentages, ratios and proportions herein are byweight unless otherwise specified.

This completes the description of the preferred and alternateembodiments of the invention. Those skilled in the art may recognizeother equivalents to the specific embodiment described herein whichequivalents are intended to be encompassed by the claims attachedhereto.

1. A method for reducing aluminosilicate containing scale in a Bayerprocess comprising: adding to a Bayer liquor an aluminosilicate scalereducing amount of a non-polymeric reaction product resulting from thereaction of: a first molecule which is an amine-containing smallmolecule and a second molecule which is an amine-reactive moleculecontaining at least one amine-reactive group per molecule and at leastone —Si(OR)_(n) group per molecule, where n=1, 2, or 3, and R=C₁-C₁₂alkyl, aryl, H, Na, K, Li, or NH₄.
 2. The method of claim 1 in which theamine containing molecule is selected from the group consisting of:isophoronediamine, C,C,C-trimethylhexanediamine, hexanediamine,meta-xylenediamine, 4,4′-methylenebiscyclohexylamine,1,2-diaminocyclohexane, saturated fatty amines, unsaturated fattyamines, N-fatty-1,3-propanediamine, and any combination thereof.
 3. Themethod of claim 1 wherein the amine-reactive molecule, is selected froma list comprised of 3-glycidoxypropyltrialkoxysilane,3-glycidoxypropylalkyldialkoxysilane,3-glycidoxypropyldialkylmonoalkoxysilane,3-isocyanatopropyltrialkoxysilane,3-isocyanatopropylalkyldialkoxysilane,3-isocyanatopropyldialkylmonoalkoxysilane,3-chloropropyltrialkoxysilane, 3-chloropropylalkyldialkoxysilane, and3-chloropropyldialkylmonoalkoxysilane, and any combination thereof. 4.The method of claim 1 wherein the reaction product is a product of areaction between the first molecule with a second molecule and also witha third molecule wherein the third molecule is an amine-reactivehydrophobic molecule with a molecular weight of less than 500 daltons.5. The method of claim 4 in which the amine-reactive hydrophobic smallmolecule is selected from a group consisting of C₃-C₂₂ glycidyl ether,C₃-C₂₂ isocyanate, C₃-C₂₂ chloride, C₃-C₂₂ bromide, C₃-C₂₂ iodide,C₃-C₂₂ sulfate ester, C₃-C₂₂ phenolglycidyl ether, and any combinationthereof.
 6. The method of claim 1 in which the amine containing moleculeis selected from the list consisting of cocoalkylpropanediamine,oleylpropanediamine, dodecylpropanediamine, hydrogenizedtallowalkylpropanediamine, and tallowalkylpropanediamine.
 7. The methodof claim 1 in which the reaction product comprises molecules having astructure according to that of Formula I:


8. The method of claim 1 in which the reaction product comprisesmolecules having a structure according to that of Formula II: